Intank filter bowl de-aeration outlet shroud and filter bowl and filter assembly including the same

ABSTRACT

An in-tank filter bowl de-aeration shroud for a hydraulic or oil reservoir includes an outlet shroud surrounding the filter bowl outlet at a proximal end thereof and having a shroud fluid outlet at a distal end thereof with a larger opening than an opening of the filter bowl outlet. The outlet shroud may be formed as or include a diverging member surrounding the filter bowl outlet at a proximal end thereof and having a diverging member fluid outlet at a distal end thereof, wherein the member diverges from the proximal end to the distal end thereof. The outlet shroud may further include a central deflector positioned within the diverging member and combining with the diverging member to form an annular passage to the diverging member fluid outlet.

RELATED APPLICATIONS

The present application is a continuation of international patentapplication serial number PCT/US2015/025618 filed Apr. 13, 2015 andwhich published as WO 2015-157,775 on Oct. 15, 2015, which publicationis incorporated herein by reference. International patent applicationserial number PCT/US2015/025618 claims the benefit of provisional patentapplication Ser. No. 61/978,256 filed Apr. 11, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to de-aeration of hydraulic fluid within areservoir, and more specifically to de-aeration of hydraulic fluid froma return line filter within a reservoir.

2. Background Information

Hydraulic reservoirs are used to hold hydraulic fluid that can beutilized by hydraulic systems, such as used in heavy machinery,including cranes, backhoes, demolition shears, bulldozers, and the like.Within the meaning of this application hydraulic fluid will be inclusiveof hydraulic fluid and oil, synthetic oil, bio-fuels, and fuels, whichare sometimes collectively referred to as industrial fluids. Inhydraulic systems, it is important to keep the hydraulic fluid free ofdebris. Consequently, filter units or filter assemblies have beenincorporated in the hydraulic systems to filter debris from thehydraulic fluid.

U.S. Pat. Nos. 6,116,454; 6,475,380, 6,508,271 and 7,252,759 disclosehydraulic reservoir designs that incorporate specific filter assembliestherein (i.e. in-tank filter elements), and these patents areincorporated herein by reference. The filter elements can be on theoutlet lines, as shown in the '454 patent or in the inlet lines as shownin the '380 and '271 patents. A filter element on the outlet or suctionside of a hydraulic reservoir is generally a simple strainer. Placingthe filter element in the inlet or return lines that extends to thereservoir, as shown in the '271, '380 and '759 patents provides certainadvantages relating to the energy required by filtration and returningof the fluid to the reservoir.

The large majority of in-tank filter elements for hydraulic reservoirsutilize a return line filter element of some kind. One known or commonexample is a forming a partition or separate bowl structure within thehydraulic reservoir and incorporating a top mounted, or drop-in, filterelement therein. A similar known configuration is to have the filterelement as part of a larger filter assembly with integrated bowl whichis “dropped” into the top of the container with the return linesconnected directly to the head of the filter assembly. This filterelement is also a top mounted structure. The term “top mounted” refersto access or mounting direction in that the filter element is accessedand replaced through the top of the reservoir, such as in the '271 and'759 patents.

Air is detrimental to hydraulic systems because it can cause numerousproblems, including Reduced Thermal Conductivity, Higher Oil andHydraulic Fluid Temperatures, Oil and Hydraulic Fluid Deterioration,Reduced Hydraulic Fluid and Oil Lubricity, Cavitation, Higher NoiseLevels, Reduced Bulk Modulus (Increased Compressibility), ReducedComponent Efficiency, and Reduced Dielectric Properties.

With new government regulations and other manufacturing pressures, manyequipment manufacturers are decreasing hydraulic fluid reservoir sizesto save space & weight. It can be more difficult for air to dissipatefrom hydraulic fluid with the resulting reduced surface area in thesmaller fluid reservoir sizes. Further space restrictions may not allowthe reservoir shape itself to be optimized for de-aeration of the fluid.

The prior art fails to adequately provide de-aeration of hydraulic fluidfrom a filter bowl in a hydraulic fluid reservoir, particularly in areservoir of reduced size. It is an object of the present invention toovercome the drawbacks of the prior art and to provide an apparatuswhich de-aerates hydraulic fluid within a reservoir. It is a furtherobject of the present invention to provide a de-aeration design that canbe incorporated into the filter bowl and/or the filter assembly design,or alternatively, added as an accessory to an existing filter bowl.

SUMMARY OF THE INVENTION

At least some of the above objectives are achieved by using an in-tankfilter bowl de-aeration shroud according to the present invention.

One embodiment of the present invention provides an in-tank filter bowlde-aeration shroud comprising an outlet shroud surrounding the filterbowl outlet at a proximal end thereof and having a shroud fluid outletat a distal end thereof with a larger opening than an opening of thefilter bowl outlet.

The in-tank filter bowl de-aeration shroud according to one embodimentof the invention may provide that the outlet shroud is cylindrical.Further the in-tank filter bowl de-aeration shroud may include adiverging member within the outlet shroud and surrounding the filterbowl outlet at a proximal end thereof and having a diverging memberfluid outlet at a distal end thereof, wherein the member diverges fromthe proximal to the distal ends thereof. Further the in-tank filter bowlde-aeration shroud may include wherein the diverging member has a bowlshape in cross section, and wherein the diverging member fluid outlet isspaced from the shroud fluid outlet.

The in-tank filter bowl de-aeration shroud according to one embodimentof the invention may provide a central deflector positioned within thediverging member and combining with the diverging member to form anannular passage to the shroud fluid outlet.

The in-tank filter bowl de-aeration shroud according one embodiment ofthe invention may provide that the outlet shroud is formed as adiverging member immediately adjacent the filter bowl outlet at aproximal end thereof and diverging from the proximal end to the distalend thereof, and wherein the diverging member has a conical shape incross section. The in-tank filter bowl de-aeration shroud according toone embodiment of the invention may further include a central deflectorpositioned within the diverging outlet shroud and combining with thediverging outlet shroud to form an annular passage to the shroud fluidoutlet, wherein the central deflector extends to the filter bowl outlet,and wherein the central deflector has a conical shape in cross section.

One embodiment of the present invention provides an in-tank filter bowlwith de-aeration shroud comprising a filter bowl configured to receive afilter element therein and having an outlet at a distal end thereof; andan outlet shroud surrounding the filter bowl outlet at a proximal endthereof and having a shroud fluid outlet at a distal end thereof with alarger opening than an opening of the filter bowl outlet.

One embodiment of the present invention provides an in-tank filterassembly comprising a filter element; a filter bowl configured toreceive the filter element therein and having an outlet at a distal endthereof; and a diverging member surrounding the filter bowl outlet at aproximal end thereof and having a diverging member fluid outlet at adistal end thereof, wherein the member diverges from the proximal end tothe distal end thereof.

These and other advantages of the present invention will be clarified inthe description of the preferred embodiments taken together with theattached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to one embodiment of the present invention;

FIG. 2 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to another embodiment of the presentinvention;

FIG. 3 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to another embodiment of the presentinvention;

FIG. 4 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to another embodiment of the presentinvention; and

FIG. 5 illustrates experimental results for the present invention.

FIGS. 6A and 6B are velocity profile schematics of testing on a priorart in-tank filter bowl;

FIGS. 6C and 6D are velocity profile schematics of testing on an in-tankfilter bowl with a de-aeration shroud according to FIG. 1;

FIGS. 6E and 6F are velocity profile schematics of testing on an in-tankfilter bowl with a de-aeration shroud according to FIG. 4;

FIG. 7 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to another embodiment of the presentinvention;

FIG. 8 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to another embodiment of the presentinvention; and

FIG. 9 is a schematic illustration of an in-tank filter bowl with ade-aeration shroud according to another embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to de-aeration of hydraulic fluid within areservoir 10, and more specifically to de-aeration of hydraulic fluidfrom a return line filter within the reservoir 10. It is important tonote again that within the meaning of this application hydraulic fluidwill be inclusive of hydraulic fluid and oil, synthetic oil, bio-fuels,and fuels. The construction of the reservoir 10 is well known in the artand may be formed as a roto-molded structure the specific configurationof which is often determined by the associated environment within whichis must be secured. The reservoir includes an inlet through the filterassembly 12, and one or more outlets (not shown). The reservoir 10 mayalso include conventional elements such as a drain, baffles, mountingfeatures and the like, not shown herein.

The filter assembly 12 includes a top 14 having the inlet and associatedline connections, an outside-in “drop in” filter element (or cartridge)16, a filter bowl 18 configured to receive the filter element 16 thereinand includes a filter bowl outlet 20 at a distal end thereof that isbelow the general fluid level line 22 within the reservoir 10. Thefilter element 16, such as available from the applicant SchroederIndustries, will typically seal around the outlet opening 20. Theseaspects of the filter assembly 12 and the reservoir 10 are generallyconventional and known in the art and are not discussed further herein.

FIGS. 1-4 and 7-9 are schematic illustrations of the reservoir 10 withan in-tank filter bowl 18 provided with distinct de-aeration shrouds 30according to distinct embodiments of the present invention.

In the embodiment of FIG. 1 the in-tank filter bowl de-aeration shroud30 includes a cylindrical outlet shroud 32 surrounding the filter bowloutlet 20 at a proximal end 34 thereof and having a shroud fluid outlet36 at a distal end 38 thereof. The outlet 36 has a larger opening thanan opening of the filter bowl outlet 20. The cylindrical outlet shroud32 may have a diameter approximate the diameter of the filter bowl 18.The cylindrical outlet shroud 32 may be formed integral with the bowl18. However the cylindrical outlet shroud 32 may also be coupled to theoutlet 20 via a threaded coupling 45. The coupling 45 can be attached tothe cylindrical outlet shroud 32 by ribs (not shown) or similarconnections.

The shroud 32 can provide directional control of the emission of thediffuse de-aerated fluid 56 into the reservoir 10. This directionalcontrol may be used to further accelerate de-aeration of the fluid andmay not always be downward as shown in the simple examples of FIGS. 1-4.For example adding a 45 degree or 90 degree (or any desired anglebetween 0 and 90 degrees) bend to the distal end 38 of the shroud 30 canbe used for further directional control (with the shroud 32 beingrotated to the desired outlet configuration in a 360 degree arc). Thedesired direction for the outlet 36 is a function of the particularshape of the reservoir 40.

In operation aerated fluid 52 exits the outlet 20 and decelerate withinthe cylindrical outlet shroud 32 allowing air bubbles to coalesce in thecylindrical outlet shroud 32. The diffuse de-aerated fluid 56 entersinto the reservoir 10 at the outlet 36. Large air bubble will form inthe proximal end 34 before re-entering the flow path and exiting thecylindrical outlet shroud 32 and floating to the surface 22 in path 54.

In the embodiment of FIG. 2, the shroud 30 further includes a divergingmember 42 within the outlet shroud 32 and surrounding the filter bowloutlet 20 at a proximal end 44 thereof and having a diverging memberfluid outlet 46 at a distal end 48 thereof, wherein the member 42diverges from the proximal end 44 to the distal end 48 thereof. In theembodiments of FIG. 2, the diverging member 42 has a bowl shape in crosssection, also known as a bell shape. The in-tank filter bowl de-aerationshroud 30 of FIG. 2 the diverging member fluid outlet 46 is spaced fromthe shroud fluid outlet 36. In operation the shroud 30 of FIG. 2 issubstantially the same as FIG. 1, with the diverging member 42 willaffect the velocity profile and the re-entering of the air bubbles intothe flow path.

In the embodiment of FIG. 3, the shroud 30 further includes a divergingmember 42 within the outlet shroud 32 and surrounding the filter bowloutlet 20 at a proximal end 44 thereof and having a diverging memberfluid outlet 46 at a distal end 48 thereof, wherein the member 42diverges from the proximal end 44 to the distal end 48 thereof. In theembodiments of FIG. 3, the diverging member 42 is a conical shape andthe diverging member fluid outlet 46 is laterally aligned with theshroud fluid outlet 36 as shown. In the embodiment of FIG. 3, the shroud30 further includes a central deflector 62 positioned within thediverging member 42 extending from a rounded proximal end 64 to a distalend adjacent the outlets 36 and 46. The central deflector 62 combinewith the diverging member 42 from the position of the proximal end 64 toform an annular passage to the shroud fluid outlet 46. The centraldeflector 62 is shaped to form the annular passage which increases incross section in the direction toward the shroud fluid outlet 46.

In operation the shroud 30 of FIG. 3 is similar as the shrouds 30 ofFIGS. 1-2, with the diverging member 42 designed to control the velocityprofile and allow de-aerated fluid 56 to exit and air bubbles to followseparate path 54.

The embodiment of FIG. 4 is analogous to the shroud of FIG. 3, whereinthe shroud 30 includes a diverging member 42. In the embodiment of FIG.4 the member 42 serves the function of outlet shroud 32. The divergingmember 42 surrounds the filter bowl outlet 20 at a proximal end 44thereof and has a diverging member fluid outlet 46 at a distal end 48thereof, wherein the member 42 diverges from the proximal end 44 to thedistal end 48 thereof. In the embodiment of FIG. 4, the diverging member42 is a conical shape and the diverging member fluid outlet 46 iseffectively the shroud fluid outlet 36. In the embodiment of FIG. 4, theshroud 30 further includes a central deflector 62 positioned within thediverging member 42 extending from a proximal end 64 to a distal endadjacent the outlets 36 and 46. The central deflector 62 combine withthe diverging member 42 from the position of the proximal end 64 to forman annular passage to the shroud fluid outlet 46. The central deflector62 is conically shaped wherein the central deflector has a conical shapein cross section and the central deflector 62 forms the annular passagewhich increases in cross section in the direction toward the shroudfluid outlet 46. The central deflector 62 of embodiment 4 has a proximalend 64 which extends to the filter bowl outlet 20.

The concepts of the present invention have been bench tested asevidenced in FIG. 5. The test was performed by injection of air into thetesting fluid and measuring the turbidity as a higher fluid turbiditymeasurement is associated with higher aeration. The air injection isshown with the high or spiking turbidity measurements to the left of thegraph 70, and thus the more rapid the graph drops from the injectionpoint the greater the de-aeration of the tested system. The base testing72 was a standard bowl 18 with no additional shroud 30. Second, anin-tank filter bowl 18 with a de-aeration shroud 30 according to FIG. 1was tested. A third test utilized an in-tank filter bowl 18 with ade-aeration shroud 30 according to FIG. 4 was tested. Having thecylindrical outlet shroud 32 alone was not as effective as the conediverging member 42 and central deflector 62, although both can be seento be improvements over the standard bowl 18. The shroud 30 design ofthe present invention provided superior de-aeration results as shown(the lower most graph). FIGS. 6A and 6B further illustrate the testingshown in graph 70 and are velocity profile schematics of testing on aprior art in-tank filter bowl graphed at 72. Similarly FIGS. 6C and 6Dare velocity profile schematics of testing on an in-tank filter bowl 18with a de-aeration shroud 30 according to FIG. 1 shown at 74 in graph70; and FIGS. 6E and 6F are velocity profile schematics of testing on anin-tank filter bowl 18 with a de-aeration shroud 30 according to FIG. 4shown at 76 in graph 70.

In the embodiment of FIG. 7 the cylindrical outlet shroud 30 is somewhatsimilar to the design of FIG. 2 and further includes a one-way checkvalve 39 (also called an aeration outlet) at the proximal end 34, whilein the embodiment of FIG. 8 the cylindrical outlet shroud 32 includes acircular array of aeration outlets 40 at a proximal end 34 thereof whichare surrounded with a gas permeable-liquid impermeable membrane 41. Inthe embodiments of FIGS. 7-9, the shroud 30 further includes a generallyannular passage 50 between the diverging member 42 and the outlet shroud32 to allow at least gas to flow within the outlet shroud 32 to theproximal end 34 of the outlet shroud 32.

In the embodiment of FIG. 9, the diverging member 42 has a conical shapein cross section, and the distal end 48 of the diverging member 42 iscoupled to the outlet shroud 32. Like the embodiment of FIG. 8, theembodiment of FIG. 9 has the cylindrical outlet shroud 32 including acircular array of aeration outlets 40 at a proximal end 34 thereof whichare surrounded with a gas permeable-liquid impermeable membrane 41.

In operation of the embodiments of FIGS. 7-9, returning fluid isdirected through filter assembly 12 through the top 14, then through thefilter element 16 within the bowl 18 and out of the bowl outlet 20 in agenerally conventional fashion. The aerated fluid is shown exiting atarrows 52. The increasing area within the diverging member 42 results ina slowing of the fluid allowing for greater removal of air from thefluid through coalescing air bubbles, the path of which is showngenerally at arrows 54 in embodiments 2-4. The air will flow upwardlyalong shroud 30 through the passage 50 to the area at the proximal end34 of the shroud 32 adjacent the diverging member 42. In the embodimentshown in FIG. 7, the air collecting in the area at the proximal end 34of the shroud 32 adjacent the diverging member 42 will flow through oneway check valve 39 and flow to the surface in the large coalescedbubbles through path 54.

In the embodiments shown in FIGS. 8 and 9, the air collecting in thearea at the proximal end 34 of the shroud 32 adjacent the divergingmember 42 will flow through aeration outlets 40 and through the gaspermeable liquid impermeable membrane 41. The de-aerated fluid shownwith arrows 56 will flow through outlet 36 into the reservoir tank 10.

The shrouds 30 according to the present invention may be formed of anymaterial that is suitable for interaction with the fluid in thereservoir 10, although plastic or sheet metal may be most economical.The shroud 30 may be formed as an add-on unit which allows forretrofitting existing reservoirs 10 and filter bowls 18. The shroud 30may also be integral with the filter bowl and the bowl may be integralwith a drop in filter assembly.

Whereas a particular embodiment of this invention has been describedabove for purposes of illustration, it will be evident to those skilledin the art that numerous variations of the details of the presentinvention may be made without departing from the invention as defined inthe appended claims. The scope of the present invention is intended tobe defined by the appended claims and equivalents thereto.

What is claimed is:
 1. An in-tank filter bowl de-aeration shroudcomprising an outlet shroud surrounding the filter bowl outlet at aproximal end thereof and having a shroud fluid outlet at a distal endthereof with a larger opening than an opening of the filter bowl outlet,wherein the outlet shroud is formed as a diverging member immediatelyadjacent the filter bowl outlet at a proximal end thereof and divergingfrom the proximal end to the distal end thereof, further including acentral deflector positioned within the diverging outlet shroud andcombining with the diverging outlet shroud to form an annular passage tothe shroud fluid outlet and wherein the central deflector extends to thefilter bowl outlet.
 2. The in-tank filter bowl de-aeration shroudaccording to claim 1 wherein the diverging member has a conical shape incross section.
 3. The in-tank filter bowl de-aeration shroud accordingto claim 1 wherein the central deflector has a conical shape in crosssection.
 4. An in-tank filter bowl with de-aeration shroud comprising: Afilter bowl configured to receive a filter element therein and having anoutlet at a distal end thereof; and An outlet shroud surrounding thefilter bowl outlet at a proximal end thereof and having a shroud fluidoutlet at a distal end thereof with a larger opening than an opening ofthe filter bowl outlet and further including a diverging member withinthe outlet shroud and surrounding the filter bowl outlet at a proximalend thereof and having a diverging member fluid outlet at a distal endthereof, wherein the member diverges from the proximal to the distalends thereof.